It is well-known in the art that certain devices that process signals cause distortion of the signals between an input and an output. Distortion can be linear or non-linear.
It is known in the art to address issues of distortion by applying pre-distortion to a signal, which pre-distortion is an estimate of the inverse of the distortion effect. In this way the effect of distortion can be countered.
Linear distortion can be dealt with relatively easily by applying pre-distortion, as the linearity of the distortion allows the distortion to be accurately predicted, such that an effective pre-distortion can be applied.
Non-linear distortion is, however, more complicated to address, insofar as the distortion is unpredictable and therefore difficult to model. In the prior art there are known algorithmic techniques for generating pre-distortion coefficients for a pre-distortion stage, which attempt to model the distortion.
Determining the required pre-distortion coefficients, particularly to counter both memory and non-memory effect distortions, is difficult to achieve in an adaptive manner.
Example methods for generating pre-distortion coefficients can be found in U.S. Pat. Nos. 6,118,335, 6,741,663, 6,570,910 and 6,798,843.
Prior art techniques can be slow and difficult to implement.
It is an aim of the invention to provide an improved technique for generating pre-distortion coefficients for pre-distortion of a signal to counter the effects of distortion.